I really like Thristies Duos, but sometimes it seems like because of the gussets they get a saggy rear with the flats being so thin. Like it slides down in there. No problem when they're not big enough to walk, and if you double stuff flats it seems to stay in the snugger when they're older. The containment is great. I also really like flips with flats. I don't really like that flap on the front because it sometimes flips outward (fingerscrossed that's what they change in the new version), but they are so trim and wonderful with flats!!!